Bowser Lane in North Vancouver: Maintaining the Performance of Pervious Pavement
Note to Reader:
In 2006, the District of North Vancouver hosted the first event in the Metro Vancouver Showcasing Green Infrastructure Innovation Series. Three projects were featured – a lane, a highway and a local community. Recently, a question about maintenance of pervious pavement provided a timely opportunity for the District’s Richard Boase to provide an update on the maintenance history of the pervious pavement installed along the Bowser laneway.
Lower Capilano Area – Application of Porous Paverment on Bowser Lane
The project was initiated as the result of a petition by local homeowners to Council. The homeowners envisioned a conventional paving project. It was a member of Council who asked Staff to take a second look and identify how an innovative approach could be applied to achieve environmental objectives.
According to Richard Boase, the District’s Environmental Protection Officer, ”There is no storm sewer in the immediate area such that infiltration into the ground was the viable alternative. Based on recommendations arising from a geotechnical investigation, the foundation for the lane was over-excavated and replaced with granular material to ensure the effectiveness of the infiltration system.”
Above, in 2006 Richard Boase of the District of North Vancouver borrowed a garden hose to demonstrate the infiltration capacity of the porous pavement. Meanwhile, David Hislop ofthe City of Surrey did his own experimenting (opposite) by pouring a bottle of water and timing how long it took for the water to be absorbed into the pavement.
It was quite a sight for the neighbours when a swarm of people from around the region descended on their lane to observe what happens when water is poured on the lane pavement.
Maintenance of Pervious Pavement
Another municipality has a small parking lot which has permeable asphalt; and it has been a long time since anyone has looked at it from a maintenance point of view. In August 2013, the following question was posed to Richard Boase:
“Should we test the permeability (e.g. pour some water on the asphalt) and then perhaps get a street sweeper (vs. a pressure washer) on site. Does that seem like a good course of action?”
“What we found is that power washing tends to cause some of the aggregate in the asphalt to loosen and detach from the surface causing holes and depressions,” responded Richard Boase.
“The best way to ensure it keeps working in using the street sweeper after fairly dry periods when the road dust is nice a dry in the voids and can be easily vacuumed. Send the sweeper in every few weeks or so during dry conditions to keep it working. Rather than doing your own permeability test I would just try and get the section of road on the list for routine sweeping.”